engleski

Mitochondriopathy presenting with immune disorder

Due to ubiquitous nature of oxidative phosphorylation and dual genetic origin of respiratory chain enzymes (nuclear and mitochondrial DNA) their deficiencies can produce any symptom in any organ. However, the involvement of the immune system in mitochondriopathies is rare. We report a girl aged 20 months with combined respiratory chain defect and immunologic impairment that includes T-cell immunodeficiency and autoimmune reactions. Main clinical findings were generalized hypotonia, rotatory nystagmus, failure to thrive and respiratory deficiency due to persistent lung infections. In trachea a large spectrum of bacteria and fungi (mostly Aspergillus fumigatus) has been detected. Cytomegalovirus infection was permanent with up to 240, 000 copies of CMV DNA/ml of blood despite one year ganciclovir treatment. She had crises with fever, tachycardia and facial blushing. Laboratory findings pointed to autoimmune processes (positive anticardiolipin antibodies, positive direct and indirect Coombs test and positive antiplatelet antibodies, hypergammaglobulinemia) and immunodeficiency. The clinical impression of an immunodeficiency was supported by repeatedly increased CD4/CD8 ratio (6.3 ; normal 0.97-2.3) with significant decrease of CD8 T cells (9%). Flow cytometric analysis of intracellular staining of IFN-gamma and IL-4 in CD4 and CD8 T cells showed three times very low IFN-gamma in CD8 T cells (0.5-1% ; reference range 2-7%). The severely reduced activity of respiratory chain complexes I (3.0 U/gNCP ; normal 15.8-42.8) and IV (53.6 U/gNCP ; normal 112-351) in skeletal muscle suggested mitochondrial etiology. Sequencing of the mtDNA tRNA genes did not reveal pathogenic mutations and mtDNA depletion was excluded by real-time PCR suggesting a mitochondrial translation defect.

mitochondriopathy; immune disorder

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